In conventional processes for manufacturing absorbent articles such as disposable diapers or sanitary napkins, heat-roll devices are generally used for joining superposed sheets. Another known joining method is to perform joining by using a laser beam. Patent Literature 1, for example, describes a method involving: transporting a sheet laminate in which a plurality of sheets are laminated while deforming the sheet laminate into a shape conforming to the peripheral surface of a rotary roller having a laser-beam transmissive section in the peripheral surface; and, in the meantime, irradiating the sheet laminate with a laser beam from the inside of the rotary roller, and thus fusion-bonding the sheets in the sheet laminate.
Further, Patent Literature 2 describes the manufacturing of a wrapping bag having sealed edge sections made by fusion-bonding a front-side member and a back-side member, wherein a long film laminate in which a front-side member film and a back-side member film are laminated is irradiated with a laser beam and is cut and separated (molten and cut) into a plurality of pieces, and, simultaneously, the two films at the molten/cut section are fusion-bonded, to thus form the sealed edge sections. It should be noted that Patent Literature 2 is silent on how to fix the film laminate upon irradiating the film laminate with the laser beam; what Patent Literature 2 suggests is a technique of irradiating, with a laser beam, a film laminate which is in a non-fixed, free state, and cutting and separating (melting and cutting) the film laminate.
Further, Patent Literature 3 describes a technique of: superposing a plurality of metal mesh plates; and, in a state where the metal mesh plates are held in tight contact by using a clamping tool, irradiating a non-clamped section (cutting path) in the metal mesh plates with a laser beam, and thus cutting all of the sheets together to form a metal mesh cloth, and simultaneously, welding together the cut surface created in the metal mesh cloth by the laser beam.